Firstborn Get the Brains 467
Dekortage writes "Eldest children have higher IQs than their siblings, according to a recent study by Norwegian researchers. The study focused on men, particularly 'on teasing out the biological effects of birth order from the effects of social status,' but indicates that the senior boy in a family (either by being firstborn, or if an elder brother died) has an average IQ two or three points higher than younger brothers. As noted in the New York Times coverage, 'Experts say it can be a tipping point for some people — the difference between a high B average and a low A, for instance... that could mean the difference between admission to an elite private college and a less exclusive public one.'"
IQ != Intelligence (Score:4, Informative)
Maybe first born are just home bodies, and thus spend more time studying.
Re:Ugh IQ... (Score:5, Informative)
In this study, they had 241,310 subjects. If memory serves me right, the population standard deviation is 15 points, so we have a margin or error along the order of 15 divided by the square root of 241,310, or 0.03. That is, two orders of magnitude smaller than 3 IQ points, which to you 'seems almost within the margin of error'.
Of course, the actual margin of error depends on other things, such as how many children were firstborn in the sample, how many were secondborn, etc. Still, with such a large sample, the final standard deviation should be much smaller than a single IQ point, making their conclusions statistically interesting. And, in fact, if the results were not statistically significant, they wouldn't get published very easily, and certainly not in Science.
Significant? Yes...meaningful, no. (Score:2, Informative)
Statistically, when you have a large number of individuals in your study (e.g., 250,000 is a huge number) you have a large amount of statistical power to detect minor differences.
In this case, while they detected a significant difference in IQ scores (whether or not IQ scores measure actual intelligence is subject of a different post), the difference may not have any practical meaning - "2 or 3 points" on a scale that has a standard deviation of 15 points is a very small effect (and thus has little practical meaning).
Re:Man, little brothers really have it bad... (Score:5, Informative)
> I also wonder if being a middle child has any effect on IQ...
Well, the article said if the first-born dies the second born's IQ jumps up. You know what you have to do...
Re:2 or 3 points? (Score:5, Informative)
It's a little more complicated than that, of course, since the "n" here has to be applied to each group separately; for the sake of argument, let's assume the sample was equally divided between first-, second-, and third-borns, that means about 80000 in each group, which means the SE is about 0.053. This is plenty to detect the kind of differences they're talking about.
Re:How about the $$$? (Score:3, Informative)
His analysis of all these things led him to believe that academic underachievers of a certain vein learn creative ways to get around things, or are out to prove people wrong regarding others saying they'll never amount to anything due to poor grades.
Re:How about the $$$? (Score:3, Informative)
http://www.payscale.com/research/US/Job=Attorney_
More like, "almost a 6-figure income after 20 years". You, like many non-lawyers, grossly overestimate how much lawyers are paid.